Project description
New theoretical approach to describing the electron-boson coupling
The interaction of electrons with bosons influences the spectral properties of solids in a profound way. Bosons can be crystal lattice vibrations (phonons), collective charge-density fluctuations (plasmons) or bound states of electrons and electron holes (excitons). The GW approximation produces accurate calculations of the quasiparticle energies across a range of materials. Bosonic excitations are described through the time-dependent density-functional theory (TDDFT). Currently, there are few approaches that describe the electron-boson coupling. The EU-funded COUPE project proposes a new combination of GW and TDDFT that couples quasiparticles to all kinds of bosonic excitations. This combination relies on a recently developed 'connector theory' that allows the use of results from the homogeneous electron gas to describe inhomogeneous materials.
Objective
Spectroscopic characterization of matter is ubiquitous in modern material science. Increased resolution and precise control over radiation sources have led to numerous discoveries of previously inaccessible spectroscopic signatures, often linked to complex excitation processes. The main challenge in their interpretation is the fact that excitations are coupled through interactions. A striking signature for this is that spectra often consist of one or more dominant peaks (called quasi-particle), followed by a series of secondary structures (called satellites). The latter, which can be very strong, are pure interaction effects and may be interpreted in terms of coupling of a quasiparticle to a bosonic excitation of the material: a plasmon, exciton, phonon, or any other boson. To solve the electron-boson problem, and, first of all, to set up the description in terms of the most pertinent quasiparticles and bosons, is a major challenge of condensed matter theory. COUPE will face this challenge. Today, quasiparticles are most often described in the GW approximation to many-body perturbation theory, whereas for bosonic excitations one can resort to time-dependent density-functional theory (TDDFT). Only a few approaches exist to describe the coupled problem, with severe limitations. For example, a cumulant expansion on top of GW describes plasmon satellites, but cannot couple to spin excitations, and there is yet no systematic way for improvement. COUPE proposes a new combination of GW and TDDFT which couples quasiparticles to all kinds of bosonic excitations. This combination relies on a recently developed “connector theory” (CT), which allows using results from the homogeneous electron gas to describe inhomogeneous materials. COUPE will further apply it to the simulation of phase transitions in magnetic and superconducting materials under study at the synchrotron SOLEIL in Paris. Preliminary model results confirm the great potential of the approach envisaged in COUPE.
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques. See: The European Science Vocabulary.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques. See: The European Science Vocabulary.
- natural sciences physical sciences condensed matter physics quasiparticles
- engineering and technology mechanical engineering vehicle engineering aerospace engineering satellite technology
- natural sciences physical sciences atomic physics
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Programme(s)
Multi-annual funding programmes that define the EU’s priorities for research and innovation.
Multi-annual funding programmes that define the EU’s priorities for research and innovation.
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H2020-EU.1.3. - EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions
MAIN PROGRAMME
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H2020-EU.1.3.2. - Nurturing excellence by means of cross-border and cross-sector mobility
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Topic(s)
Calls for proposals are divided into topics. A topic defines a specific subject or area for which applicants can submit proposals. The description of a topic comprises its specific scope and the expected impact of the funded project.
Calls for proposals are divided into topics. A topic defines a specific subject or area for which applicants can submit proposals. The description of a topic comprises its specific scope and the expected impact of the funded project.
Funding Scheme
Funding scheme (or “Type of Action”) inside a programme with common features. It specifies: the scope of what is funded; the reimbursement rate; specific evaluation criteria to qualify for funding; and the use of simplified forms of costs like lump sums.
Funding scheme (or “Type of Action”) inside a programme with common features. It specifies: the scope of what is funded; the reimbursement rate; specific evaluation criteria to qualify for funding; and the use of simplified forms of costs like lump sums.
MSCA-IF-EF-ST - Standard EF
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Call for proposal
Procedure for inviting applicants to submit project proposals, with the aim of receiving EU funding.
Procedure for inviting applicants to submit project proposals, with the aim of receiving EU funding.
(opens in new window) H2020-MSCA-IF-2019
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Net EU financial contribution. The sum of money that the participant receives, deducted by the EU contribution to its linked third party. It considers the distribution of the EU financial contribution between direct beneficiaries of the project and other types of participants, like third-party participants.
91128 PALAISEAU CEDEX
France
The total costs incurred by this organisation to participate in the project, including direct and indirect costs. This amount is a subset of the overall project budget.